Driver drowsiness poses risks to traffic safety. Various mechanisms have been previously used to attempt to detect driver drowsiness. For example, cameras in an interior of a vehicle may be used to monitor a driver's eyes, whereupon a percentage of time the driver's eyes are closed may be determined. When a driver's eyes are closed for a percentage of time in a given period of time higher than a predetermined threshold, driver drowsiness may be determined. However, use of interior cameras to monitor a driver's eyes may be unreliable, and moreover, increases vehicle cost, and manufacturing complexity by requiring an in-cabin sensor that otherwise would not be required to be included in a vehicle.
Another current mechanism for attempting to detect driver drowsiness includes using cameras external to a vehicle to determine whether a driving pattern is inconsistent with road conditions, e.g., whether a driver is veering in and out of a lane. However, exterior cameras needed to obtain information about a road may not be reliable, particularly when road conditions are poor, weather is severe, etc. Further, as with use of interior cameras, using exterior cameras and/or other types of sensors to determine a vehicle's position with respect to a roadway can add costs, weight, and manufacturing complexity to a vehicle.
In short, present mechanisms for detecting driver drowsiness may suffer from shortcomings, e.g., related to unreliability, especially needed sensors, etc.